I am in halifax and got my square from a guy here who had three. It is easy to pick one up in the states and bring it across the border (i got my zxi 1100 in buffalo). Just look up the process and have the docs needed (like recall info, safety info). Trailers can be alot more of a pain (have to get safety checks and registrations, pay a ~$175 import fee). Declare it as parts or repair, and pay the gst. There is no import tax on things without wheels (skidoos+skis) just tax on the sales recipt.
As for parts they are easy to get, dealer, ebay, forums. It is service that can be difficult (there is no one that can work on my zxi electronics, yamaha techs dont see many sj's) But superjets are realitively simple to work on, and the guys online have done everything with them and are a very helfull bunch. If I was you I would drive down to the states and pick one up for 1500-2500. As a newbie a high compression stroker motor may be more than you want to start. Anywhere across the border you could easily get a square with a 701/head/pipe/prop for under $3000, and would have a better than stock boat for 1/3 the price of a new o8 sj